It is a common practice to insert tubes into a patient to convey fluids to or discharge fluids from the patient. These procedures facilitate recovery of the patient but may at the same time lead to complications due to the environment in which they operate.
One such environment is when a respiratory tube is inserted through the pharynx and larynx into the lungs of a patient. This tube conveys oxygen with a relatively high humidity to the lungs which produces a very humid atmosphere within the lungs and within the tube. The high moisture content allows secretions to be deposited on the wall of the tubes and if left unattended leads to secondary infections. Normally an attempt is made to remove the secretions by inserting a suction tube into the endotrachial tube. However, when such a tube is inserted, only a small portion of the secretions is removed so that the cleaning is ineffectual, Moreover, the procedure is relatively long, leading to restriction in the cross-section of the tube and some discomfort to the patient during the procedure.
The secretions also significantly reduce the cross-sectional area of the tube, increasing the resistance to fluid flow in the tube.
An attempt to use a mechanical device such as a scraper or swab to clean the tube would face similar problems in that the secretions may be dislodged into the patient's lungs.
A balloon catheter is an elongate tube having a plurality of radial passages through the wall of the tube usually at one end. A membrane surrounds the passages so that upon introduction of pressure into the tube, the membrane is inflated. The catheters may be used in a variety of applications where it is desirable to seal one part of a tubular passage from another. For example, the catheter might be inserted into a blood vessel to isolate a portion of the blood vessel while plaque or the like is removed. Frequently such catheters are utilized with two lumens, one of which is used to inflate the membrane and the other of which can be used to extract materials from within the vessel.
Particular care must be taken when using balloon catheters, as overinflation could cause damage to the vessel against which the balloon engages, or alternatively cause damage of the catheter with serious consequences. Moreover, care must also be taken during insertion and extraction of the catheter to ensure that it does not unintentionally inflate or deflate. There is therefore a need for a device to control the inflation and deflation of a catheter.
It has now been recognized that a balloon catheter may offer a solution to the cleaning of such tubes provided appropriate control can be exercised when using the catheter.
Within the context of cleaning an ETT, overinflation of the catheter may cause it to bind on the walls of the tube and so inhibit its extraction. Likewise, unintentional inflation of the catheter during insertion may push secretions into the lung rather than removing them as the catheter is extracted.
It is therefore an object of the present invention to provide a device for controlling the inflation of a balloon catheter to permit its use in a number of environments and to provide a method of using such a catheter in the cleaning of tubes.
According therefore to one aspect of the present invention, there is provided a device to control the inflation of a balloon catheter comprising;
a variable volume chamber having an outlet for connection to a lumen of a balloon catheter, PA1 an actuator movable relative to the chamber to vary the volume of the chamber and expel air therefrom to inflate said balloon, PA1 a releasable latch operable to inhibit movement of the actuator relative to the chamber; and PA1 an abutment to limit movement of the actuator upon release of the latch to thereby limit the volume of air expelled from the chamber to inflate the catheter, said abutment being adjustable relative to the actuator to vary the volume of air expelled.
The device of the present invention provides for a controlled inflation and prevents unintentional inflation of the catheter. It has been recognized that this device makes it possible to insert a balloon catheter into a tube in a deflated condition, inflate the catheter and extract it from the tube to wipe the surfaces of the tube and remove secretions. Thus the device may be used in combination with a catheter as a method of cleaning such tubes.
According therefore to a further aspect of the present invention, there is provided a method of wiping the inner wall of a tube comprising the steps of inserting into the tube in a deflated condition a balloon catheter, inhibiting inflation of the catheter until a predetermined location has been attained, subsequently inflating said catheter to engage said inner wall with a force to permit relative movement between the wall and the catheter and withdrawing said catheter from said tube while inhibiting further inflation.